I know it is not precision optics but is there a certain curve you have to put on the round part of the lens? I'm guessing you have to really peer around all sides to view the message or is that all in focus in the field of view?

Well, there are some size ratios on the internet for simple lenses. Keep in mind that the thickness of the wine glass pieces will be fixed. So when you do your ratios, you will already know the thickness. I decide on my size ratios and started grinding. I first grind towards the outer diameter size I need. As far as the curve I make a 45 degree grind from the edge and then a 60 degree grind from the middle of the 45 angle. Do this with your 100 grit then move onto the 220 grit. This creates the curves main shape. Move onto other grits (400 and up) and polish using a spinning and rocking motion. This will knock off the sharp edges. Never stop in one place or you will get a flat spot, keep the lens moving at all times when grinding or polishing. This will give you a nice dome. Please note glass cuts fast, so use lots of water.Since I am doing this free hand I get mixed results (not precision). I make a few extra and take the best for my project or I need to go back and regrind for better results... The style of lens helps out in getting to your magnifying goals - concave vs convex etc... I really struggled with the focal length. Viewing through the lens on the egg the message is directly across, not a lot of searching required. You should have seen my back up design for a moveable message to put it in focus. I am glad I did not have to go with the backup design.I selected the wine glass because of the clarity. For cheap clear glass it works out well. My thought is that I can at least make a lens as well as the early inventors. So, I guess I just try and do my best.More questions as you try this, just let me know. I will try to explain it again. Scott